The invention relates to an rpm governor of a fuel injection pump for internal combustion engines, which includes an adjustable stop for limiting the maximum injection quantity, a piston which is hydraulically displaceable counter to a restoring force to vary the position of the stop, and pressure control apparatus for controlling the pressure exerted on one end of the piston within a work chamber to determine the position of the piston and stop.
In a known governor of this type, the piston is exposed to fuel from the suction chamber of the fuel injection pump, the pressure of which varies in accordance with engine rpm. The piston is thus displaced in one direction as the rpm increases, and in the opposite direction with decreasing rpm. The adaptation course itself is determined by a curve in the jacket face of the piston, which is scanned and which must have a different course for each engine or for each additional further engine characteristic taken into account. Any pressure fluctuations in the suction chamber of the injection pump at the same time cause a change in adaptations, that is, in the piston position, which is expressed in a correspondingly poorer operation or in changed exhaust gas figures for the engine.